1. Field of the Invention
The present invention relates to a post-processing device and a post-processing method which are able to perform post-processing control and control processing of drive signals at the time of driving in a stapler, puncher or the like to be connected to an image formation (recording) device.
2. Description of the Related Art
A conventional image formation device such as a printer or a copying machine has a post-processing device. In the post-processing device, the edges between sheets on which images are formed (which are printed) are registered and post-processing including stapling and punching is performed, and thus the post-processed sheets are discharged and are stocked. Such a post-processing device is provided beside or above the sheet outlet of the body of an image formation device, and the post-processing device has a registration structure that sheets printed by the image formation device are supplied successively from its outlet to perform post-processing. A device, which is known as the post-processing device, has a finishing function that the sheets are registered in the direction (lengthwise direction) parallel to the feeding direction of the sheets as well as in the direction (widthwise direction) vertical to the same feeding direction, and thus the registered sheets are subjected to post-processing such as stapling and are discharged from the device.
As other known post-processing devices, a device has only a stacking function that sheets printed by the image formation device are stacked in sequence on a discharge tray without post-processing, and a device has a function that post-processing based on the above finishing function and mounting-processing based on the stacking function.
(1) For instance, a finisher as a staple post-processing device has a function that the registered sheets are discharged to a stacking tray and are stacked on the tray.
However, a rush current flowed to the stapler is large when the stapler is driven at the time of stapling, which is a way of post-processing the printed sheets, and the driving current of the stapler increases depending on the type and number of sheets to be stapled, thus imposing, a heavy burden on a power source connected to the post-processing device.
(2) A staple post-processing device, which operates by being connected to an image formation device, has a driving power supplied from the image processing device or a power source included in the staple device.
However, where power is supplied from the image formation device to the post-processing device and power is also supplied to any other connected device or unit (for instance, an optional paper feed device, a scanner for reading the subject copy or the like) from the image formation device, an increase in current at the time of operating each of these devices results in a greater power supply capacity and a higher cost. When the operational timing is overlapped between devices, a current is increased largely and temporarily though for a short period of time.
(3) In an image formation device according to the prior art described in the Japanese Patent Application Laid-Open No. 2000-321940 for instance, the control for changing the timing of operation is performed so that peak current occurred between the connected devices is not overlapped each other, thus reducing the peak current and the average current of the whole image formation device.
However, according to the Japanese Patent Application Laid-Open No. 2000-321940, when a plurality of consecutive printing jobs are performed, the control for changing the actuation timings of the plurality of devices connected to the image formation device is necessary, and the complication of the control method and a throughput as the image formation device overall may be induced. The peak value of current consumption differs according to the type of the optional connectable devices, and the control for changing the operational timing may be complicated according to the form of connection.
(4) Another problem is that, when sheaves of sheets are to be post-processed, post-processing by stapling, punching or otherwise may induce a loud noise due to an increased driving power of the operation members. When a plurality of post-processing is to be performed at the same time, the noise of device at operation as well as the aforementioned increased power may induce a big problem.